1. Preheat oven to 350°F and grease your mini loaf or 9x5 pan. Line with parchment if desired.
2. In a large bowl, whisk pumpkin, sugars, milk, egg, melted butter, and vanilla until smooth.
3. Sift in flour, baking soda, baking powder, pumpkin spice, cinnamon, and salt. Stir until no flour streaks remain.
4. Pour half the batter into the prepared pan, then sprinkle with half the cinnamon swirl mixture.
5. Add remaining batter and top with the rest of the swirl. Use a knife to gently swirl.
6. Bake 25–28 minutes for mini loaves, or 45–50 minutes for full loaf. Check doneness with a toothpick.
7. Cool in pan 10 minutes, then remove and cool completely on a wire rack.